Masteri-Farahani, M. , and Modarres, M. . "Encapsulation of Keggin-type phosphotungstic acid into the mesopores of SBA-16 as a reusable heterogeneous catalyst for the epoxidation of olefins", Scientia Iranica, 24, 6, 2017, 2993-3001. doi: 10.24200/sci.2017.4492